Wellington Phoenix believe they are the on the verge of achieving a goal they set themselves at the start of the season.

The New Zealand club wanted to qualify for the finals for the first time in the A-League this season and all but secured their spot in the top six with a 1-0 win over Adelaide United in Christchurch on Saturday night.

Coach Ricki Herbert said the attitude of the players had changed considerably in recent times and with a top-four finish now on the cards, the confidence is right up there to mix it with the best teams in the league.

"We set the goal that making the playoffs was the basic requirement this season. Should we do that, it's definitely not a case of 'job done'. We'd love to make the top four and secure home advantage because we're very, very tough to beat at Westpac Stadium," Herbert said.

"Our attitude and belief is that we have the team that could go all the way."

The Phoenix take on the Central Coast Mariners this Friday night back at their hom ground in Wellington in a match that could see them book their place in the A-League finals for the first time.